Internal-combustion engine



Feb. 9 1926, 1,572,397

P. A. LAWRENCE INTERNAL COMBUSTION ENGINE Feb. 9, 1926. 1,572,397

P. A. LAWRENCE INTERNAL COMBUSTION ENGINE Filed March 29, 1921 3 Sl'leeS-Shel'l 2 Cam Slm# FIG.8

Feb. 9 ,i 1926.

P. A. LAWRENCE INTERNAL COMBUSTION ENGINE Filed March 29, 1.9-21 5 Sheecs--Shee1'l 5 C sam opl FIG. 1.5

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Patented AF eb. 9p, 1926.

PATENT 1,512,391 OFFICE.

PAUL ANDREW LAWBENGE, von GRAND ISLAND, NEBmisxA.

INTERNAL-COMBUSTIN ENGINE.

Applicationy led'larch 29, 1921. SerialfNo. 456,702. I

To all 'whom t may concern: f

Be itknown that I, PAUL ANDREWLAW- RENCELa citizen of the United States, residing at'Gland Island,'in the county of Hall and Stateof Nebraska, have invented a new and useful Improvement in Internal-Combustion Engines, of vwhich the following is a specification. I

My .invention relates to an improved means of injecting liquid fuel into the cylinder of an internal combustion engine of va certain constant pressure type. As the invention relates to a definite type of engine,

it is essential to an understandingl of the principles thereof to illustrate and describe' the engine in detail'. i

The invention` is particularly applicable to the use of heavy oils and for engines which have to work. undera variable speed and load, such as marine, tractor and automobile engines. The'type of engine chosen for illustration in these drawings and specifications is an engine of this type and is controlled by hand; -v This type of engine operates by compressin air to such a pressure that the heat re su ting from the compression of the charge of air is sufiicient to ignite the fuel as fast as it isinjected into the cylinder. It dogs not simply compress the air and'theii inject the vfuelinto the air behind the piston, but bring's `a' current of air.and a current of oil together in a port and, as fast as they unite in combustion, they pass on to the cylinder and out of the way of the incoming air and oil. In this manner, the lastportion of oil meets with as pure air as the first portion and combustion is perfect throughout.

This is done by means ef an air chamber attached to the cylinderheadand, prefer'- abl formed within a hollow -of the head an 'closed by a poppet valve which permits air to Aentery the airchainber', but prevents itl 'from returning unless held open by sonic external force or means. The air chamber contains compressed air of a pressure equal Ato the compression pressure of the engine.

Said compressed air4 beingsupplied by the engineitself through the air chamber valve retaining' a portion of the' air compressed by the piston, instead of ermitting all the air it contains to enter tie cylinder. vThe air chamber is connected to the cylinder by a port into which the-fuel is injected, and

where it meets the air flowing into the cyl-1.

inder from the air chamber while the air the pressure .is too low cliainber'valve is being held open.

when for spontaneous ignition,r the spark plug may be used to ignite the fuel.. The spark plug is also necessary to ignite'the .fuel when'starting a cold engine.

The two stroke cycle engine, but, as this type of engine-is equally welhadapted for four stroke cy\c'le of operation, likewise, equallyvadapted to both kinds.

. The injection of liquid fuel in this type of/fengine, in theform of a 'finely divided spray, without the admixture of air, gives satisfactory results, where the speed engine is quite uniform, so that the size of the nozzle and, consequently, the velocity'of entrance of Vthe fuel may be Well harmonized. Butwhere the speed is variable, it is manifestly impossible to maintain a proper velocity through a nozzle of fixed i size for the best 4atomizing effects; Moreover, in small sized engines, the quantity 'of oil injected per ,stroke is so small that the of the engine described and illustratedis a the invention is,

size ofthe nozzle for liquid fuel injection becomes so minute that it is liable to besible to "use largei'nozzles and also t'o make it possible to, securea nearly uniform velocit-v of the fuel through a fixed sized nozz e with a variable speed of the engine.

The invention has; as one .of its objects,

the automatic regulation of the quantity of air tobe mixed with the oil, whereby,- when the engine is running at low speed, thequantity 'ofl air ,ente-ring with the oil is a maxi-v mum, while, when the engine is running at high speed, the quantity of air entering per stroke is a' minimum. 'The proportions of air to oil, therefore, varies'with the speed of the engine, while the quantity of oilinjected er stroke may remain the same or otherwise, but the two fluids together always properly fill the nozzle for the best atomizing effects.` y Y' In engines of the Diesel type, the oil is sprayed into the cylinder by a heavy current of air, which atomizes the oilv and creates aA current "or stirring action in the cylinder, to bring about perfectcombustion; stirring action, necessary in-the Diesel engine, fis'not required in the type of engine herein described and to'which my invention is particularly adapted, because'the fuel is injected into a moving body of air, instead of into a mass of motionless air. Engines of. the Diesel type require an air compressor to compress the air for this purpose but, in the engine described, no compressor is needed, because the engine stores part of the air it compresses, in the reguhrr processes .of operation, Vfor the purpose of starting and manipulating theengine. In my invent1on,. a portion of this stored up air is used to mlx with the fuel and is simply pumped into the engine cylinder with a small air 1 pump without the necessity of compress- 'ing it. f

The invention consists, essentially, of a: duplex pump, pumping oil with one plunger and the air with another plunger.- lThe oil ispumped against the full pressure of vthe engine, but the air is simply taken from the air bottle or from the air chamber of the engine and pumped into the cylinder with the oil. The manner in which the invention is carried out in practiceand the type of engine to which it is applicable will be better understood by referring to the drawings, but it must be understood that'the invention is not limited to any particular form of ,pumpused or mechanism employed, but to toI the cylinders for scavenging and chargwithout vibration.

ing the cylinders. This air pump is also a tivo'cylinder, single acting machine. It will be yseen 'that the cranks for the engine cylinders are angularly spaced 180 degrees apart and the cranks for the air pump cylinders are, likewise, 180 degrees apart. This fcature'givesa nearly perfect balance of` moving parts and permits of high speed Referring to the drawings i Figure 1 is a top view of the fuel pump, with the cap, z-l, removed.

Fig. 1a is a cross sectionalview of the air pump cylinder through one set of the valves upon the section plane, Fig. l." is an end view of the cylinder only. Figure 2 1s oil pump 'a longitudinal sectionk of the pump, taken upon' a vertical section plane.

passing through the center line of 'both the oil and air pump cylinders.

Fig. 2" is across sectional view of the air The A of the shaft.

Itakes place through invase? Fig. 2a is a cross sectional view of the oil pump cylinder taken upon the plane, D. Fig. 2c is an end view of the heart cam and yoke, which operates the fuel pump.

Figure 3 is a vertical cross section of the pump upon the section plane, E, of Figure v 1, to show the driving mechanism 'f the pump rod.

Figure 4 is a cross section of the oil pump cylinder u on the section plane, B, and shows the y-.pass for regulating the pump pressure and the working pressure of the engine.

Figure 5 is a section through the arm, z--3, to Vshow how it is secured to the shaft, 2-4.

' Figure 6 is the admission valve. It is taken upon a vertical section plane passing through the center line of the valve. One of-these valves is required for each engine cylinder, and it is operated by a cam on the cam shaft of the engine.

Figure 7` is a top vie-w of the engine .and the low pressure air pump cylinders, for scavenging and charging the engine cylinders. In this view, one-half of the cylinder head of the engine is cut away to show the upper surface of the cylinder. By reason of the valvesin the cylinder head there is not suflicient room for'the entire chamber to he formed in the head, and a portion is, therefore, formed in a yseparate vessel attached to the rear part of 'the cylinder head, but which is not shown in'this view.

Figure l8 is a partial front elevation and sectional 4view of the engine and air pump. A vertical section plane passes through onehalf of the engine cylinder, showing one ofthe pistons andy rod, and another passes through the air pump cylinder in like manner. section plane passing through the center line The engine and pump cylinders are mounted side by side upon the same frame and operate yfrom the lsame crank shaft. Asthe pump has very little work to do andas the pressure never rises above 10 lbs., the workingparts can be made very light. The air pump uses a piston valve in the head fordistributing the air to the engine, which results in a positive volumetric deliveryat highspeed. The inlet-valves for the engine are inet'he head. The exhaust ortsin the walls of the cylinder` which t e piston uncovers at the end of the stroke. The inlet valves are The entire frame is cut by a vertical positively opened bv cams on a camI shaft.

The same cam shaft is used for o erating der upon the line, A-A of Fig. 8. In this view, the head is removed in order to show the location of the intake valve; butfthe 13W air chamber, which is attached to the cylinder head, is left in its normal position and 'is shown in elevation.- It shows the intake valve mechanism from the cam to the Valve. Flgure 1s a Vertical section through the Y cylinder head, showing the intake valves and their mounting in `the head. The section` plane passes 'through the center of the valve stem andcuts the cylinder `head `longitudinally along the line, B, Figure 7..

Figure .11 shows the admission cam and mechanism used to terminate the fuel admission period from zero to about threefourths ofthe power Vstroke of the engine. Fig. 1la is a vertical section through the cylinder head uponv the plane, F, liigure` 7,

and shows how fthe air chamber valve, b, is

held open while the filial enters the com-- bustion port through the nozzle, a 1. It also shows how favorably the spark plug, f, is located to ignite theV fuel, in caseI the er1- gine is cold or, the compression pressure too low for spontaneous ignition. Figure 12 is. a diagrammatical plan of the air and` oil piping and the apparatus for injecting the fuel.

i Figure 13 isa diagrammatical construction of the valve timing and pressure functions'of the working Huid of the engine, and will be readily understood by those skilled in the art to which the diagrams relate. is with the .position of the crank in the position shown in Figure 9 vand is indicated in the diagram by the figure, 1. ln all the views, similar figures correspond to the same parts, so. thatparts may be located in the diferent views and their re# regular running. From here the Oil passes flown into the suction port, 0 4. as shown in Fig. 2*?. Upon the suctlon stroke, the oil -passes through the ball valve, 0 6, and

port, 0 7, into the pump cylinder and from here it is forced up through the ball Valve, 0 10, into the discharge port, 0 ,11,.dur ing the discharge strok The suction of thepump is singlelacting, but the discharge is double acting. This is accomplished by the differential etlect of the rod and piston. The piston rod, 0 is en larged to form a piston. Packing is inserted at 0 25 and at 0 26. The enlarged The starting point in the valve timingportion `is twice the area of the rod, so that `when thepiston moves to the right, the de,-

liveryo'f oil takes place by reason of the displacement of the enlarged portion minus the displacement of the rod, while, when thc piston moves `to the left. the,deliveryresults from the displacementifr plunger action of the rod. i

The oil required by the engine passes outz through the hollowrscrew, 0 12, the cock` 0 13, and the pipe, o p, to the admission valves, while the surplus oil passes through the spring loaded lay-pass, 'shown in Figure' 4, back ,to the suction port, 0 4. The pump delivers its fullcapacity and' thc varying demands of oil by the engine are vmet by by-passing'the surplus.

0 23, the spring, 0 18, is adjusted and the discharge pressure of the pump is adjusted fob correspondingly.

The air pump is of the ordinary double acting construction` receiving air on' one side of the piston While delivering air on the other side. The suction and 'discharge valves for 'one end of the cylinder are 'shown in the view Fig. la. The air from the air chamber of the engine enters through the pipe, 3/ 7 1, vand reaches the suction port, g/ 4. It then passes through the suction valve, 3/ 6, and the port, f1/ 7, into the cylinderand is then delivered through the port. g/ 8, and the discharge valve, g/ 10, into the discharge port, jz/ 11, and out through the cock. 1/ 13, and the pipe, g/ p, to the admission Valves. A similar set of valves is placed at the other endof the cylinder to makethe pump double acting.

The pump body is heavily made'and is threaded to receive the oil pump on one side and the air pump on the other side. T he `top opening is threaded i#to receive a cap.

2 1. This makes the interior of the pump body air tight. The discharge from the air pump is connected to the pump body by the pipe, j1/ 23. so the interior ot` the pump body is under the same pressure as the discharge pressure of both the oil and the air pump. This feature serves a two fold purpose. It entirely relieves the packing, ,4: 25 'and 0 26, of high pressure and also forms a pressure equalizer for the air pump.

Sufficient lubricating oil 1s kplaced in the body to lubricate the'moving parts.

The air `pump displacement is about ten 125.

times the volumetric oil pump displacement. The plston rd of the pump is driven bv vthe arm, 2 3, which is secured to the shaft,

2 4. A ringl of packing is inserted at ef- 15, to prevent leakage for the pressure 1n the body, Z, is very high. An outside arm, 2 5, connects to the reciprocating member, z-7, which is actuated by the heart cam, 2 9. The heart cam imparts a uniorm motion to the, pump pistons, which results in a steady discharge flow, there being only aslight interruption at the ends of the stroke. These interruptions are compensated for by an air chamber on the oil 'pump and the reserve air in the body of the pump for the air pump.

The admission valve, shown in Figure 6, has a nozzle-composed offa small round hole through which the oil and air are forced into the engine cylinder.v The hole is of sucha size that vit requires a definite pressure to force the fluid through the nozzle, lthereby generating suiiicient velocity to properly atomize 'the oil when tstrikes the root' of the combustion port, as illustrated in Figure 11a. If no air were mixed with the oil, the hole in the nozzle would be considerably too large for proper atomizing, even at the lhighest speed of the engine, but, if all the air which the pump delivers had to pass through the nozzle at high engine speed, the hole would be too small and would v was made by means of the valve shown in Figure 4. The quant-ity of oil injected is dependent upon the load the engine'v is carrying, but, by varying the amount of air injected with oil in harmony with the speed of the engine, the velocity of fluid entrance is kept quite uniform. lThis feature is ,accomplished by means of the spring loaded air by-pass, shown in the view to the right of Figure 2; This by-pass-consists essen- 40 tially of a steel ball, y--15, held to its seat e by the spring, :1j-17, and which is ad'ustable by the screw, 1/-18. By removing t e plug,

1h-20, a screw driver may be inserted and adjustment effected. This by-pass determines the ultimate pressure with which the fuel is driven tlirou h the nozzle, and whenever the speed of t e engine becomes high enough, a portion of the air by-passes, but the quantity of oil injected is not' interfered with. No change of adjustmentis required when once properly set, and the operating pressure of the engine may be raised or lowered without interference or effect from this by-pass.

Figure 6 is a detailed view of the admission valve. The operating member or rod consists of'three pieces and serves the twofold purpose of acting asa valve and for the admission of fuel and a push rod to open the air chamber valve, b, shown in Figure' 11a. The lower rod, a-a, is threaded to receive the upper rod, or. The upper rod is drilled hollow, as shown by the dotted lines, and has ports drilled to communicate ywith `the hollow interior. The rod, a, is enlarged at the upper end to` form a valve had and also to receive -the nozzle member, a-1,

which screws into the rod, a. The valve head fiber instead of metal, the cushion of soft 4 packing is notneeded. The rod is` operated by the mechanism, shown inFigure 11, and

it will beseen that the opening of the ad mission valve is always accompanied by the l y opening of the air chamber valve. 4The oil and air is forced into the valve by the fuel.

pumpv through the pipes, o-p and y-p,` and the interior of thevalve, w-o, is always under the full discharge pressure of the fuel pump. In order to balance this pressure'v gtendency of raising the valv rod, the lower portion, (1f-a, is made the same diameter as the valve head. When the valve is open during the admission period,4 the pressure is about v5() lbs. higher in the valve than in the cylinder or combustion port, and the-oil and air enter the linder as follows The oil enters t rough the hollow screw, a-5, the 'ports a21 and a-A, to the interior of the rod, a. The air enters through the hollow screw, 0,-19, the ports, a-17. and a-16, to the interior of the rod, a. Here the oil and air mix'and to ether they pass up the hollow interior, then t rough the ports, a-3, around the valve head, through the ports, a-2, through the hollow nozzle member, aFl, and out through the nozzle. The nozzle is directed upward, so that the fuel is projected at high velocity against the hot cylinder head, whlch dashes-the oil into avery fine-spray.

Owing to the volumetric displacement of' the rod, .ar-a, a greater portion of the oil enters during the early part of the valve opening or while the rod is ascending and less when the rod descends. This is a favorable feature for small high speedvengines. but is not desirable for large slow speed engines. In the later case, the airconnectiom a-20, is connected together with a-6 by the same hollow screw, and the upper connection and ports are omitted or'plugged. In this position, the oil enters `the cylinder in response to the `accelerating engine piston demands for the entire admission period. The nozzle must always point in the proper direction and, therefore, the rod must be ke tl from turning. This is accomplished by t e member, a-1 2, which may be turned until the nozzle is properly directed and remains in place by the pressure of the spring, a13. The application of the invention to the type of engine for which it is adapted will be understood by a description of the oper? ation of the engine.

From Figure .9,it will be seen that the piston comes very close to the head and, therefore, .the volumetric clearance is reduced to a very `small percentage.

The air scavenging pump hasv the same cylinder diameter and stroke as the engine and, therefore, delivers about one-fourth more air than the volume compressed by the engine. The cranks 4of the pump are set at 90 degrees with the cranks of the engine, so that the greater portion f the pump delivery occurs during the intake period of the engine. In this way, no unnecessary rise of pressure occurs in the pump, due to lack of harmony between these two functions.

The' fuel pump supplies f ueleto the admission valves at a constant pressure at all times, and has suicient capacity for com-A plete union with all, the air' which could possibly enter out ofllk Referring to Figure 13, the admission period of the engine, under normal operation, extends from 1 to 2 or any smaller angle. However, when starting, the admission period may be as greatas shown by the dotted lines while taking air from the air bottle.

Theexpansion period. extends to the point 3, where the piston uncovers the exhaust ports and exhaust begins. A

At 4,' the intake valve opens and air rushes in through the intake valve, ,driving out `the remaining products of combustion and filling the cylinderwith pure-air.

but vthe intake valve 1s still open, and part of the air. returns through the 4intakelva-lve. At 6, the intake valve closes and compression begins. A s At 7, the compression has reached the same pressure as the pressure in the air chamber, and delivery to the air chambe begins. l

At 1, the delivery is completed and approximately one-half of the ,air compressed has been delivered into the air chamber.

The admission valve is just opening and the air chamber valve, b, is held from its seat, as shown in Figure 11a. As the piston advances, fuel enters through the nozzle, a1, and air from the air chamber enters through the port, C-l, and the open valve, b. T he temperature of the airis high enough to ignite the oil as fast as it enters. In starting,V when the temperature is not high enough, ignition is effected by the spark Plug f- The adnnsslon period 1s increased or decreased, in accordance with the load on the engine, by rocking the shaft, k, to and fro. This advances or recedes the follower, laf-2,- to different positions of the cam, a-v-z. v `The dotted lines show thev position of the camfollower, k-2, in position of zero cutl olf. In this position no fuel entersthe enthe cylinder `for the latest` gine cylinder, and the valve, b, is not held from its seat. It, therefore, acts as a check valve and the engine runs as an air compressor, delivering air to the air lchamber but receiving none in return. This results in rapidly bringing the engine to a stop.

It will be seen that the pressure inthe air chamber, A, passes through a cycle, for every engine cycle. The pressure rises from 7 tol and falls from 1l to 2, which is the same as l to 7.

The injection air for the fuel pump is conveniently taken from the air chamber, as shown in Figure 9. An air cooler, c-y, is attached to partially cool the air and condense the water. The air then passes through the cock, 0-'-y-1, and the pipe,

y-p-'1, shown in Figure 12, to the fuel pump. The fuel is taken from the-oil tank,

`when running, or from the gasoline tank,

when starting, by means of vthe three-way cock, shown in Figure 12. The air and oilfrom the fuel pump are conducted in the pipes, z/'p and o-p, respectively, tothe admission valves,I where they mix and enter the cylinders.

The engine is started by pressed air from the air bottle. The air for this purpose being stored by the enginel in the regularprocess of operation. The engine is stopped by reducing the cut-Lofil to `Compressed air has, heretofore, been used x for driving the fuel into the cylinder, the At 5,v the piston again covers the ports` processes being attended by a division of the fuel and a stirring action of the air bep hindvt-hepiston, in prder to bring the fuel into .contact with the air vfor combustion.

-force, independently of .the others motive force.

'What I claim as new and desire to secure by Letters Patent is: 4

1. In an internal combustion engine comprising a cylinder, a piston, an air chamber forming a clearance for the Aair compressed by the piston, a valve to control the flow of air between the, cylinder and air chamber, and a combustion port forming a passage for the air between the cylinder and air chamber; the combination of apump com'- i prising means for pumping fuel from an ordinary source of s upply and air from the said air chamber: a valve for receiving said fuel and air and injecting said mixture into the combustion port; and means for opening said air chamber valve during `the said injection period.

2. In an internal combustion engine of the constant pressure type having an air admitting comchamber closed by a valve and containing compressed' air of a pressure approximately equivalent to the normal working pressure of the engine, and an admission valve for 'each cylindertoadmit a mixture of air and liquid fuel during the admission period of the power stroke of tlie engine; the combination therewith of a pump for delivering both liquid fuel and air under constant pressure to the said admission valves;v

3. In an internal combustion engine of the type described the combination of Ian air chamber; an airl chamber valve to close the opening of said air chamber to the cylinder; an admission valve for injecting a mixture of fuel and air; means for opening said air chamber valve during fuel injection; a cani for driving saidJ admission valve; a cam follower interposed between said cam and admission valve; Aandineaiis for shifting said- 'follower backward and forward thereby changing the fuel injection period.

4. Ink an internal combustion engine, of the type described having an admission valve for injecting a mixture of liquid fuel' and air into the cylinderof the engiiie, the combination therewith of a pump for supplying liquid fuel and air at constant pressure to the admission valve and having means for adjusting the discharge .or injection pressure of said pump.

v5. In an internal combustion engine of the type described having an .admission valve ,for injecting a mixture of liquid fuel and air iinto the cylinder of the engine, tlier combination therewith lof, a pump for supplying liquid -fuel and air under constant ressure to the admission valve means for adjusting'said injection pressure to raise or lower the norma working pressure of the engine, and means for regulating the roportion" of liquid fuel and air delivere to the said admission valve.

6. In an internal combustion engine of the type described the combination of an admission valve for each cylinder for injecting a mixture of liquid fuel and air; a p ump` for delivering liquid fuel andair under constant pressure; an adjustable spring loaded by-pass valve .for by-passing the surplus l oil; and an adjustable spring loaded by-pass valve for by-passing the surplus air.

7. In un internal combustion engine of the typeA describedhaving a source of compressed air supply of a pressure approximately equal-.to the normal compression pressure of ythe engine, the combination of an admission valve for each` cylinder for injecting a mixture of liquid -fuel and air; a pump for supplying liqluid fuel and air to said `admission va ves, saidA pump receiving liquid fuel without pressure and delivering it at normal. injection pressure; said .pump also receivingncompressed air from the engine of approximately normal compression pressure and delivering it at normal injection preseY sure.

8; In an internal combustion engine liaving a cylinder; a piston moving therein and connected to a. crankshaft; anv air chamber connected to the cylinder containing compressed air and receiving a portion o f the. air compressed by the motion of the plston; ,a Valve to control theopening of said air chamber into said qcylinder; and a fuel admission valve forinjecting a mixture of liquid fuel and air into said cylinder during aportion of the power stroke; the combina tion therewith of aVv fuel pumpfor supplying said admissionV valve with liquid fuel and air, said pump receiving liquid fuel at any pressure lower than the injection pressure required bythe vengine and ydelivering said fuel tot e admission valve at the required' injection pressure of the engine; said pump also re 'ving compressed air from `the air chamber of said engine .and delivering saidL air.f to said admission valve at the required injection pressure of the engine'. i

9. In an internal combustion engine the combination of a cylinder; 'a piston moving therein and connected to a crank shaft; an air chamber, connected. to the cylinder; la

j valve to control the opening between said air chamber and cylinder; an admission valve for injectinui a mixture of liquid fuel and air into said cylinder; means for operating said admission valve to inject fuell into said cylinder for some definite portion of the power 'stroke depending upon the load on,l

-the.engine; means for retaining said airr chamber valve in an open position during the` fuel injection period of the ower stroke; a fuel pump receiving liqui fuel .from an ordinary source of supply and delivering it to said admission valve at .injection ressure; a byl-pass valve for b -pass ing` t e surplus liquid fuel; means oradjusting said by-pass valve; :said vfuel pumpv also receiving compressed air from the said air chamber of the engine and delivering it to the said admission valve at injection` pressure; a byrpass valve for lay-passing the surplus compressed air at the higher speeds of the engine; and ineans'for adjusting the and independent; a cam shaft carrying a cam of proper contour for each admisison valve; a cam follower for each cam, making contact with said cam b` a projection or nose; anda control shaft aving an larm for each cam follower to which said cam follower-is hinged, and swings freely about the point, of suspension so that in rocking said control shaft to and fro said' cam follower moves forward or backwardacross the said cam, thereby changingthe point of contact' of said cam follower with said cam and,

consequently, the length of time the admission valve remains open.`

1l. In an internal combustion engine 1njecting fuel into the cylinder vsilnultaneously with the inflow of air from an ai@ chamber and in which the fuel injection always begins at a fixed pointof the engine crank position but is cut oil at diiferent posit-ions of said .crank travel, the combination there-I with of a fuel injection cam; a cam follower hinged at one end and making contact with said cam by a projection near its free end and carrying a push rodon its back surface; an oscillating shaft' having an arm to which said v'cam follower ,is hinged; and a concurrent contour between the leading surface of the cam and the back sur- PAUL ANDREW LAWRENCE., 

